package j07jiekou;
class A implements I1{
    public void f1(){
        System.out.println("i am f1");
    }
}

class B implements I1{
    public void f1() {
        System.out.println("i am B f1");
    }
}
public class J1 {
    public static void main(String[] args) {
        A a = new A();
        a.f1();

        new B().f1();//推荐
    }
}


interface I2{
    public abstract void f100();
    public abstract void f200();
}

abstract class C3 implements I2{
    @Override
    public void f100() {

    }
}
class C4 extends C3{
    @Override
    public void f200() {

    }
}
